This invention pertains to heterocyclic carbon compounds which have drug and bio-affecting properties. In particular, this invention relates to 10-imidoylphenoxazines and 10-imidoylacridans effective as smooth muscle relaxants. The term "smooth muscle relaxant" has a definite meaning in pharmacology and medicine. It generally refers to agents known to relax smooth muscle in blood vessels, in the bronchial tree and in the gastrointestinal, biliary, urinary and uterine tracts. Two types of smooth muscle relaxants are known; namely, those that produce their effect by direct action on smooth muscle (e.g., papaverine or aminophylline) and those that produce their action primarily via the autonomic nerve supply (e.g., isoproterenol and atropine). The compounds of the instant invention are thought to be direct acting. Another feature of the invention is a therapeutic process for producing smooth muscle relaxant effects in mammals by administration of the 10-imidoylphenoxazines and 10-imidoylacridans.
We have previously disclosed 10-imidoylphenothiazines in our co-pending United States patent application Ser. No. 147,667, filed May 27, 1971, now U.S. Pat. No. 3,719,671, as being of interest for their intestinal relaxant and antithrombogenic activity. We have now unexpectedly discovered that another class of amidines, namely 10-imidoylphenoxazines and 10-imidoylacridans and their salts, have smooth muscle relaxant activity and, in some instances, antithrombogenic activity.